A grid of evolutionary synthesis models for different scenarios (initial mass function slope, metallicity, age, etc.) and computing a set of observables in a wavelength range extending from soft x-rays to radio is reported. The model predictions were compared with observational data for a sample of 13 star forming galaxies of different morphologies, aiming to constrain the properties of the star formation episodes taking place there. The most relevant results found are the following: the slope of the IMF (Initial Mass Function) is not universal, varying in the range 1 to 3 in starburst galaxies; there is no correlation between IMF slope and metallicity of the environment in the sample; and the interstellar absorption follows a law similar to the SMC one in regions dominated by massive stars, independently on their metallicity.